Quadrilateral vehicle

ABSTRACT

In a vehicle having a single front and rear mounted driven and steerable wheel or track, 360* steering is possible by applying drive about its steering axes. The torque developed by this drive is balanced out in the steering system, hence preventing the vehicle from being difficult to steer in one direction and easy in the other direction. This vehicle is capable of turning about its own center and requires no differential. The system is particularly adaptable to a small snowmobile and will greatly enhance its steering, traction and braking characteristics. Two centrally mounted skis are placed on the vehicle in a quadrilateral fashion to provide lateral stability.

United States Patent Watson [54] QUADRILATERAL VEHICLE [72] Inventor:Thomas A. Watson, 2720 Goyer Apt. 24, Montreal, 251, Quebec, Canada [22]Filed: April 27, 1970 [21] Appl. No.: 32,136

[52] US. Cl. ..l80/5 R, 180/946 [51] Int. Cl. ..B62m 27/02, 862d 1 1/20[58] Field Of Search ..180/5 R, 5 A, 9.24, 9.46, 21

[56] References Cited UNITED STATES PATENTS 645,272 3/1900 Scheu..180/2l 2,067,546 1/1937 Rocher ..180/21 2,846,017 8/1958 Luchterhand..180/5 3,455,405 7/1969 Parent ..180/9.46

[151 3,684,044 1 1 Aug. 15, 1972 Primary Examiner-Richard J. Johnson[57] ABSTRACT In a vehicle having a single front and rear mounted drivenand steerable wheel ortrack, 360 steering is possible by applying driveabout its steering axes. The torque developed by this drive is balancedout in the steering system, hence preventing the vehicle from beingdifficult to steer in one direction and easy in the other direction.This vehicle is capable of turning about its own center and requires nodifferential. The system is particularly adaptable to a small snowmobileand will greatly enhance its steering, traction and brakingcharacteristics. Two centrally mounted skis are, placed on the vehiclein a quadrilateral fashion to provide lateral stability.

1 Claim, 29 Drawing Figures Fischbach ..180/9.46 X

sum 2 0F 6 m a. U/allon mm mm R 9 on PATENTED AUG 15 m2 PATENTEDAUB 151912 3,684,044 v sum 3 or 6 jmawahor PATENTEDAUG 15 I972 3 6 4 044 sum aDP 6 FIG 23 QUADRILATERAL VEHICLE The invention relates to a means ofsteering and driving a four wheeled vehicle with two centrally locatedside wheels. On the center line running perpendicular to the axis ofrotation of these side wheels at the front and rear of the vehicle ismounted a wheel. The front wheel and rear wheel are mounted an equaldistance from the axis of the side wheels. The side wheels areindependently free to rotate at different angular velocities withrespect to each other, and are not drivenor steered.

The front and rear wheels are steered through equal and opposite anglesand always travel in the same circle or line, hence theyalways run atthe same peripheral velocity. When the frontand rear wheels are turnedthrough 90 from their straightposition the vehicle will turn aboutitsown center, making it highly manuverable. If they areturned between90 and 270 the vehicle will reverse without reversing the drive means. Aperpendicular line drawn from each wheel always points to the samecenter hence satisfying conditions for proper steering.

Since both wheels always travel at the same peripheral velocity they canbe driven from a single engine by means of a rigid drive system. Eachwheel has a sprocket and is chain driven from another sprocket mountednear the vertical steeringaxis of the wheel. A right angle gear drive iscoupled to this sprocket and is in turn driven by another chain andsprocket system, all of which rotate about a vertical axis. The drivesystem is such that each wheel may be rotated about its vertical axisforsteering purposes. A turning moment occurs about this vertical axiscausing the wheels to be turned about their steering axis. This reactionmay be prevented by driving the steering system through a worm gear.Steering the vehicle in onedirection would then be easy and in the otherdirection it would be difficult.

To overcome the steering difficulty each wheel may be driven by aseparate motor mounted within the wheel itself. This eliminates the needof a separate drive system .to each wheel. It makes the vehicle morecompact and places a large portion of the weight over each of the drivenwheels. The vehicle will obviously operate with onlyone engine improvingits reliability. For small, low power vehicles this approach ispractical, but not necessarily the most economical. Electric motorscould replace the internal combustion engines mounted in the wheel.

The tendency for the wheels to steer themselves in one. direction due tothe drive system may be eliminated by providing the drive in such amanner that the front and rear wheels reaction is balanced out in thesteering and drive system. The drive means is coupled to each wheel suchthat they will tend to steer in the same direction, however, thesteering system is reverse coupled so that it steers the wheels inopposite directions. The end result is that the reaction of the frontwheel is cancelled out by the rear wheel. If the drive system is notproperly coupled to the wheels the reaction forces would add causing thevehicle to want to steer into one direction only.

Chain drive is shown but the system is also adaptable to shaft and geardrive.

By connecting an electrical motor to each wheel .all four wheels maybedriven. The front and rear wheels always travel at the same velocitywith respect to each other whereas the side wheels travel at a varietyof velocities with respect to each other and with respect to the frontand rear wheels. In certain cases one side wheel may be stopped or mayeven go backwards with respect to the other side wheel. By employingtraction type electric motors and controlling their direction ofrotation the side wheels may also be powered for improved traction. Asimple controller for stopping and reversing the electric motors isattached to the steering mechanism. A more complex system with speed aswell as direction control could be developed.

In another version of the vehicle the front and rear wheels could besubstituted for tracks. This would make a highly manoeuverable vehicle,particularly adaptable to the small size snowmobile market. In oneversion the tracks could be wide enough to provide lateral stabilitywithout the need for side wheels or skis. In another version, skisorwheels could be placed at the side of .the vehicle to provide lateralstability. This arrangement is suitable for narrow snowmobiles. Vehicleswith two tracks side by side normally require a greater width to achievemanoeuverability than this arrangement and are also less efficient whenturning.

The objective of this invention is to provide a highly manoeuverablevehicle capable of turning about its own center. Another objective is toprovide a vehicle in which no slippage can occur between driven wheels,

which could tend to make the vehicle difficult to steer.

Another objective is to provide a vehicle which is capable of goodperformance on highways as well as on rugged terrain. Another objectiveis to make a compact vehicle by placing the motor and drive system ineach wheel of the vehicle. Another objective is to show a drive systemcapable of driving all four wheels. Another objective is to provide atracked Vehicle based upon the same concept, and particularly a highlymanoeuverable small size snowmobile with good traction characteristics.Other objectives will become apparent in the detailed description whichfollows:

FIG. 1 shows the position of the vehicle s four wheels when travellingin a straight line.

FIG. 2 shows the position of the four wheels when the vehicle is steeredthrough an angle less than FIG. 3 shows the position of the wheels whenthey are steered through an angle of 90.

FIGS. 4 to 15 are a vector representation of the direction of motion ofthe four wheels at various steering angles.

FIG. 16 is a side view of a vehicle employing the wheel locations asshown in FIG. 1.

FIG. 17 is a plan view of the vehicle shown in FIG. 16.

FIG. 18 is a front view of the vehicle shown in FIG. 16 taken along theline l8 18.

FIG. 19 is a vector representation of the moments of force occurring atthe front and rear wheels.

FIG. 20 is a vector representation of the forces developed in thesteering system.

FIG. 21 shows a cross sectional front view of a motor mounted withinawheel.

FIG. 22 is a plan view showing motor drive means to the two side wheels.

semblies of the vehicle shown in FIG. 27.

FIG. 29 is a partial side view of a track assembly employing its ownmotor.

FIG. 1 shows the position of front wheel 1, side wheels 2 and 4, andrear wheel 3. The distance between the centers of the wheels are equalsuch as the dashed line 1-2 equals 2-3 equals 3-4 equals 4-1. The arrow5 shows the direction of the vehicle. All wheels travel at the sameperipheral velocity.

FIG. 2 shows the wheels 1 and 3 turned through equal and opposite angles0. All four wheels turn about the center C. Wheels 1 and 3 travel indirection 5 on a circle whose radius is C-l or C-3 which are equal,hence the front and rear wheels travel at the same peripheral velocity.

FIG. 3 shows wheel 1 turned through 90 clockwise and wheel 3 through 90anticlockwise. All wheels turn about center C. The distance C-1 and C-3are equal, hence wheels 1 and 3 travel at the same peripheral velocityin direction 5. In this condition the vehicle will actually turn aboutits own center.

FIGS. 4 to give a vector representation of the direction of travel ofeach wheel as a function of the angle through which wheels 1 and 3 areturned for steering purposes. Arrows 6 and 7 indicate the direction inwhich the wheels are steered. C represents the center about which thevehicle is turning.

FIG. 4 shows the vehicle going straight forward with all wheelstravelling in the same direction at the same peripheral velocity.

FIG. 5 shows the wheels 1 and 3 steered through less than 90, with thecenter C outside the vehicle. Wheel 4 will travel relatively slow withrespect to the other wheels.

FIG. 6 shows the wheels steered through less than 90 but more than inFIG. 5, such that the center C is in the center of wheel 4, whichbecomes stationary.

FIG. 7 shows the wheels 1 and 3 steered through 90 such that the centerC is in the vehicles own center. Wheel 4 now travels in the oppositedirection to wheel 2 but at the same peripheral velocity.

FIG. 8 shows the vehicle steered beyond 90 with the center C in thecenter of wheel 2, which becomes stationary.

FIG. 9 shows the wheels steered through a greater angle than FIG. 8 suchthat the center C is outside the vehicle. Wheel 2 now reversesdirection.

FIG. 10 shows the wheels 1 and 3 steered through 180 such that thevehicle goes backwards.

FIG. 11 shows the wheels steered through more than 180 such that point Cis outside the vehicle.

FIG. 12 shows the wheels steered through a greater angle than in FIG. 11such that the center C is again in the center of wheel 4, which againbecomes stationary.

FIG. 13 shows the wheels steered through 270 with the center C again atthe vehicles center. The vehicle now turns about its own center, but inthe opposite direction to that shown in FIG. 7. Also, wheel 4 now movesin the forward direction.

FIG. 14 shows the wheels steered through more than 270 such that thecenter C is located in the center of wheel 2, which again becomesstationary.

FIG. 15 shows the wheels 1 and 3 steered through an angle greater thanthat shown in FIG. 14 such that the center C is outside the vehicle.Wheel 2 now travels in the forward direction. When the wheels aresteered through a complete 360 they will take up the positions as shownin FIG. 4.

FIGS. 16, 17 and 18 show a vehicle employing the steering system asdescribed in FIGS. 1 to 15. Both front and rear wheels are driven froma' single motor at the same peripheral velocity and are steered throughequal and opposite angles. The side wheels are freewheeling.

A motor 10 is mounted on a frame 11. A transmission and clutch 12 aremounted on top of motor 10. A sprocket 13 is driven from transmission12. A chain 14 passes through holes in frame 11, not shown, and isdriven from sprocket 13 and drives sprocket l5. Sprockets l5 and 16 andbevel gear 17 are all fixed to hollow drive shaft and bearingarrangement 18 which .rotates about steering shaft 19. Sprocket 15drives sprocket l6 and gear 17 which inturn drives chain 32 and gear 64respectively. Gear 64 drives shaft 65 which rotates in bearing 24 and inturn drives sprocket 22. Bearing 24 and shaft 19 are fixed to fork 25.Sprocket 22 drives chain 23 which in turn drives sprocket 26 attached towheel and bearing 28, which rotates about axle 27 mounted in fork 25.

Chain 32 drives sprocket 41. Sprocket 41 and gear 43 are mounted onhollow drive shaft and bearing 42 which rotates about shaft 39. Gear 43drives gear 67 which is mounted on shaft 66 which rotates in bearing 45and drives sprocket 44. Bearing 45 and shaft 39 are mounted on fork 47.Sprocket 44 drives chain 46 which in turn drives sprocket 48 fixed towheel and bearings 50, which rotates about axle 49 mounted in fork 47.

Gears 20 and 38 are attached to steering shafts 19 and 39 respectively.Shafts 19 and 39 turn in bearings 21 and 40 respectively. A shaft 30which runs in bearings 31 and 36 fixed to frame 11, has gears 29 and 37fixed to its end. Gear 29 drives gear 20 and gear 37 drives gear 38.

A steering wheel 51 is mounted on a shaft 48 running in bearing 52mounted in support 53 fixed to frame 11. Shaft 58 drives gear 54 whichin turn drives gear 55 fixed to shaft 59 running in bearing 57 mountedin support 53. Shaft 59 runs through bearings 60 and 63 mounted on frame11. A worm gear 62 mounted on shaft 59 drives gear 61 fixed to shaft 30.

Support members 33 and 68 are attached to frame 11. A side wheel 34rotates about axle 35 fixed to support member 33 and a side wheelrotates about an axle 69 fixed to support member 68. Wheels 28 and 50have a rigid drive system such that the rotation of either wheel willcause the other to move an equal amount provided the steering does notturn. The steering is prevented from turning due to wheel action, by theworm gear 62. The worm gear arrangement will not always be required,this is especially true on small vehicles. Since both wheels are rigidlycoupled they will not slip with respect to each other. This will greatlyimprove their tractive ability as compared to a vehicle using adifferential. Since the wheels 28 and 50 always travel on the same lineor circle they will always travel at the same peripheral velocity, hencethere is no need to use a differential.

As shown in FIG. 19 the drive system composed of chain 32 and sprockets16 and 41 develop a moment which causes each wheel to tend to turn aboutits steering axis in the same direction, assisting steering in onedirection but opposing it in the other. FIG. 20 shows the reaction onsteering gears 20, 29, 37 and 38, gears 29 and 37 are coupled by shaft30. Gear 20 tends to turn gear 29 in the opposite direction to thatwhich gear 37 tends to be turned by gear 38. Since the gears 29 and 37tend to turn the shaft 30 in opposite directions, a cancellation offorces occurs. This system allows the vehicle to be turned in eitherdirection with the same steering effort. If the steering and drivesystem were not properly coupled, there would be a net reaction on thesteering system, making it difficult to steer in one direction. Shaftsand gears could replace the chain drive system shown.

FIG. 21 shows a hub mounted motor and wheel arrangement which could beemployed to replace the front and rear wheels 28 and 50 and theirassociated drive system as shown in FIGS. 16 to 18.

To a fork 100, which would replace forks or 47, of FIG. 16 are mountedhollow stub axles 103 and 113. Bearings 104 and 111 are mounted on drum102 which rotates about the axles 103 and 113. A frame 114 is mounted tothese axles. A motor 105, a fuel tank 106 and a transmission 108 aremounted to frame 114. A shaft 107 transmits power from the motor 105 tothe transmission 108. A shaft 115 attached to transmission 108 protrudesthrough the frame 114. A sprocket 109 is fixed onto shaft 115. A chain110 is driven by sprocket 109 and drives sprocket 1 12 attached to drum102 through the casing of bearing 111. A wheel 101 is fixed to drum 102which in turn is driven by sprocket 112. Controls may be brought outthrough the hollow axles 103 and 113, which also serve as ventilationducts.

FIGS. 22, 23 and 24 show a system for electrically driving the front andrear wheels and also a system for powering the side wheels.

FIG..22 shows a frame 128 to which is mounted electric motors 123 and127 driving transmissions 121 and 125, through chain and sprocket drives122 and 126 respectively. Side wheels 120 and 124 are mounted on stubaxles 129 and 130, which are driven by transmissions 121 and 125respectively.

FIG. 23 shows a method of hub-mounting an electric motor and connectingpower cables such that the front and rear wheels of the vehicle may becontinuously steered through 360. The arrangement is similar to thatshown in FIG. 21.

A frame 132 is suspended on stub hollow axles 131 and 135. An electricmotor 134 and transmission 133 are mounted on the frame 132. Wires 136for motor 134 pass through the hollow axle 135 and up through the hollowsteering shaft 137 to the slip rings 143 and 144. Brushes 145 and 146make contact with slip rings 143 and 144 respectively and are mounted onpost 141 fixed to frame 140. The fork 147 is fixed to shaft 137 and inturn supports axles 131 and 135. Shaft 137 rotates in bearing 139mounted to frame 140. Steering gear 142 is mounted on shaft 137. Acontroller 138 is mounted to frame and is coupled to shaft 137.

FIG. 24 shows a circuit diagram forinter-connecting the four electricmotors to the vehicle so as to provide drive to all four wheels. A motor150 drives the front wheel, motors and 156 the side wheels and motor 157the rear wheel. Controllers 151 and 152 switch power to motor 155 andcontrollers 153 and 154 switch power to motor 156. All four controllersare ganged together and are mechanically coupled to the steering. FIG.23 shows a controller 138 attached to the steering system, thiscontroller is comprised of controllers 151, 152, 153 and 154.

Power is supplied by a source 158 which could be a diesel electric motorgenerator. Motors 150 and 157 are powered continuously while the vehicleis in motion. Motors 155 and 156 are powered in the forward or reversedirection depending upon the position of the controller. The diagramsshown in FIGS. 4 to 15 are used to determine the steering angles atwhich the side motors are switched. At certain steering angles one orploying the steering and drive principles as shown in FIGS. 1 to 15, and19 and 20. A motor 202 is mounted on a bracket 204 which is mounted onframe 201. A pulley 259 is attached to motor 202 and drives belt 203which in turn drives pulley 205. Pulleys 259 and 205 and belt 203 form aclutch and automatic transmission.

Pulley 205 drives a shaft 216 which rotates in a bearing 215 mountedonplatform 201. A sprocket 217 attached to shaft 216 drives chain 218which in turn drives sprocket 220. Sprockets 220 and 223 and gear 224are fixed to a hollow drive shaft and bearing 22] which rotates aboutsteering shaft 225 which is fixed to frame 238. Gear 224 drives gear 226fixed to shaft 228 which rotates in bearings 227 mounted on frame 238. Asprocket 230 is fixed to shaft 228 and drives chain 229 which in turndrives sprocket 231 mounted on shaft 243. Shaft 243 rotates in bearings270 mounted in frame 238. Sprockets 242 are attached to shaft 243 and inturn drive the endless track 232. Bogey wheels 239 and 241 run on axles233 and 240 respectively mounted on frame 238. Track 232 also travelsover these bogey wheels.

The shaft 225 turns about bearing 219 mounted on frame 201. A gear 206is fixed to shaft 225 and is driven by gear 207 fixed to shaft 211.Shaft 211 turns in bearing 271 mounted in upright 208 and bearing 212mounted to platform 20]. Upright 208 is mounted on platform 201. Asteering wheel 210 drives a shaft 275 which rotates in bearing 274mounted in upright 208. A sprocket 273 is attached to shaft 275 anddrives chain 209 which in turn drives sprocket 272 mounted on shaft 211.Shaft 211 drives gear 213 which in turn drives gear 214 mounted tosteering shaft 257. Shaft 257 rotates in bearing 258 mounted to platform201. Frame 245 is attached to shaft 257.

Sprocket223 drives chain 222 which in turn drives sprocket 256. Sprocket256 andgear 254 are mounted on hollow drive shaft and bearing 255 whichrotates about shaft 257. Gear 254 drives gear 253. 252 represents adrive system not shown but is identical to the one used on frame 238 atthe front of the vehicle composed of elements 227, 228, 229, 230 and231. Shaft 251 is driven by the equivalent of sprocket 231. Shaft 251rotates in bearings 276 mounted in frame 245 and drives sprockets 250which in turn drives the endless track 244. Track 244 travels over bogeywheels 247 and 249 mounted on axles 246 and 248 respectively. Axles 246and 248 are mounted in frame 245.

A ski 235 is mounted on a bracket 234 fixed to frame 201, and a ski 237is mounted on a bracket 236 also fixed to frame 201. These skis may bereplaced by wheels as shown in FIG. 16. The skis would normally be shortand wide. The sides and back of the skis could be flared upwards toassist in reversing and turning. The position of the wheels and skis inthis arrangement with respect to the track is not as critical as withthe four wheeled vehicle due to slippage. They should, however, beplaced centrally between the tracks and as far out from the sides of thevehicle away from its longitudinal center line as possible.

FIG. 29 shows a motor 260 mounted on a frame 238 of FIG. 27 driving apulley 261 which in turn drives a belt 262. Pulley 263 is driven by belt262. Pulley 263 is mounted on shaft 266 running in bearing 264 mountedto frame 238. A sprocket 267 is attached to shaft 266 and drives a chain265. Chain 265 would normally drive sprocket 231 of FIG. 28. The frame238 is mounted to shaft 225 which rotates about bearing 219 mounted inplatform 201. This motor drive system is placed on the front and rearframes 238 and 245 of FIG. 27, and replaces the motor 202 in its drivesystem.

The steering wheel 210 drives shaft 211 which steers the front and reartrack assemblies to equal and opposite angles. The motor 202 and itsassociated drive means powers the front track assembly. Chain 222transmits power from the front track assembly to the rear track assemblyboth tracks being driven at the same peripheral velocity. The side skisprovide lateral stability and their use is dependent upon applicationand the width of the track. The drive and steering system has the samecancellation system for balancing out steering moments developed by thedrive system as the vehicle shown in FIG. 16.

This arrangement is particularly adaptable to small snowmobiles. Thesystem makes it possible to construct a narrow highly manoeuverablevehicle with better traction characteristics than conventionalsnowmobiles employing a single track and ski arrangement. Present smallsnowmobiles have limited manoeuverability except for those typesemploying two parallel tracks. These snowmobiles employing two paralleltracks are normally wider than a single track vehicle if they arerequired to be highly manoeuverable. Present two track vehicles areinefficient when turning due to track drag, whereas the conceptpresented here does not exhibit as much drag when executing a turn.

This arrangement is also adaptable to off road land vehicles capable ofoperation on rugged terrain and soft surfaces. It would normally useside wheels instead of skis for this purpose. The skis or side wheelscould be replaced by a track. This track may be driven by the systemshown in FIG. 22.

The arrangement with a motor mounted on each track assembly may beemployed rather than the system using a single motor to drive bothtracks. It is somewhat more expensive but provides additionalreliability since the vehicle will operate on only one motor. Thesteering system turns the front and rear track assemblies through equaland opposite angles.

In general, the front and rear wheels or tracks form a traction meanswhich is steered through equal and opposite angles. The front and reartraction means being normally driven at a constant peripheral velocity.The traction means are not necessarily restricted to wheels or tracksbut could take other forms.

It should be noted that the drive shafts could be placed inside thesteering shafts. This would somewhat change the construction of thevehicle but the results would be similar.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

I claim:

1. A vehicle comprising a frame having a first and a second track meanswith steering shafts steerably mounted on the frame about first andsecond vertical axes respectively, means connecting the two steeringshafts for simultaneous steering in opposite directions, first andsecond vertical drive shafts coaxially mounted respectively with the twosteering shafts for rotation about the steering axes and drivablyconnected to the track means, transmission means connecting the driveshafts for rotation in the same direction and means driving thetransmission means, a first ski mounted to one side of the frame means,a second ski mounted to the other side of the frame means, said skisdisposed underneath the frame means midway between the first and secondtrack means.

1. A vehicle comprising a frame having a first and a second track meanswith steering shafts steerably mounted on the frame about first andsecond vertical axes respectively, means connecting the two steeringshafts for simultaneous steering in opposite directions, first andsecond vertical drive shafts coaxially mounted respectively with the twosteering shafts for rotation about the steering axes and drivablyconnected to the track means, transmission means connecting the driveshafts for rotation in the same direction and means driving thetransmission means, a first ski mounted to one side of the frame means,a second ski mounted to the other side of the frame means, said skisdisposed underneath the frame means midway between the first and secondtrack means.